Electric Current Increases Research Articles

Experimental and mechanistic studies on the thermo-electric synergistic catalytic oxidation of acetone over MnO2/TiO2-Ni foam catalyst

Volatile organic compounds (VOCs) cause serious environmental and human health risks and must be efficiently removed. In this work, a metal-structured catalyst of Ni foam loaded Mn/Ti oxides was used for the oxidation of acetone, a typical VOC compound. The catalyst was in-situ joule heated when applying an electric current and produced the thermo-electric synergistic oxidation (TEO) effect. Compared with conventional thermal oxidation (CTO), the oxidation rate of acetone significantly increased by 124.19 % and the energy consumption of per unit complete oxidation rate was reduced by 66.67 % in TEO reaction with a 12 A electric current at 200 °C. The efficiency gradually improved (from 16.12 % to 36.14 %) and the energy consumption of per unit complete oxidation rate decreased (from 2.85 W/% to 0.95 W/%) with the increase of electric current. Besides, the thermal (including the catalyst thermal effect and reaction gas thermal effect) and electric effects in TEO reaction were analyzed by the statistical analysis method. With the temperature increasing from 200 °C to 400 °C, the proportion of electric effect slightly decreased while that of reaction gas thermal effect increased from 5.2 % to 18.1 %. It proved that the TEO method has the advantage of improving low-temperature catalytic activity. Furthermore, the mechanism of electric effect was investigated, in which it enhances the conversion of lattice oxygen in TiO2 to surface-adsorbed oxygen species and promotes the oxidation of Mn oxides, sequentially improving the oxidation of acetone.

Weak electric current increases ceramide levels by inducing ceramide synthase expression

We previously demonstrated that weak electric current (WEC) induces the skin penetration of macromolecules by the cleavage of intercellular junctions and allows for incorporation of macromolecules into cells via endocytosis. We further showed that WEC facilitates the leakage of macromolecules from endosomes to cytoplasm and that this phenomenon correlates with increased endosomal ceramide levels. From these observations, it suggested ceramide production is induced by WEC. In this study, to investigate mechanisms by which WEC treatment increases ceramide levels, acyl chains in ceramides of WEC-treated cells were analyzed. As a result, we found that WEC increased the amounts of C16:0, C22:0, and C24:1 ceramides and that WEC induced ceramide synthase 2 expression. Therefore, we conclude that WEC activates the ceramide synthesis pathway and that increased endosomal ceramide would contribute to the leakage of macromolecules.

Effects of pulse repetition rate in static electrochemotherapy models

Electroporation alters cell membrane structure and tissue electrical properties by short and intense pulsed electric fields (PEF). Static mathematical models are often used to explain the change in electrical properties of tissues caused by electroporation. Electric pulse repetition rate may play an important role, as tissue dielectric dispersion, electroporation dynamics, and Joule heating may affect the electrical properties. In this work, we investigate the effects on the magnitude of the electric current when the repetition rate of the standard electrochemotherapy protocol is increased. Liver, oral mucosa, and muscle tissues were studied. Ex vivo animal experiments show that the magnitude of the electric current increases when the repetition rate is changed from 1 Hz to 5 kHz (10.8% for liver, 5.8% for oral mucosa, and 4.7% for muscle). Although a correction factor could reduce the error to less than 1%, dynamic models seem to be necessary to analyze different protocol signatures. Authors should be aware that static models and experimental results can only be compared if they use exactly the same PEF signature. The repetition rate is a key information to consider in the pretreatment computer study because the current at 1 Hz PEF differs from a 5 kHz PEF.

Step electrical switching in VO2 on hexagonal boron nitride using confined individual metallic domains

Vanadium dioxide (VO2) exhibits an insulator–metal transition (IMT) accompanied with a giant resistance change, which is attractive for the application of devices, such as switching devices. Since the behavior of individual domains determines the total IMT property of the VO2 sample, the steep resistance change from a single domain can be identified and utilized in a sample whose size is as small as the individual domain size. Uniquely, micro-structured VO2 thin films on hexagonal boron nitride (hBN) exhibit step resistance changes owing to the confined metallic domains. In this study, we demonstrated step electrical switching in the two-terminal VO2 sample produced on hBN. Operando structural and electric investigation revealed that the emergence of metallic domains in the micrometer space contributes to the step electric current increase. Our results indicate the use of individual metallic domains in VO2 thin films on hBN in the application of novel devices.

Graphite-Based Multianalyte VOC Gas Detection on Multichannel PCB IDE Sensor

In this article, we present the development of a volatile organic compound (VOC) gas sensor based on graphite on a printed circuit board (PCB) multiplexed interdigitated electrode (IDE) sensor. We report the effects of graphite as a sensing material deposited by the spray method and its interaction response to specific gases. In addition, we demonstrate how we designed and manufactured IDE sensors with an integrated heating circuit and thermistor element, as well as the 55- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{L}$ </tex-math></inline-formula> microchamber, which contributed to the fast detection of gases. All experiments were performed with four IDE sensors to verify the reproducibility and sensitivity of the proposed methodology. Our results highlight that acetone presented the highest detection sensitivity, with an electric current increase of ± <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100~\mu \text{A}$ </tex-math></inline-formula> at a 200-ppm cycle with a response of 0.92 s and full recovery at 2.62 s. Furthermore, the developed sensors were able to detect and distinguish between acetone, methanol, isopropanol, ethanol, and chloroform gases. The sensors exhibited outstanding stability and repeatability when evaluated after six months. The sensors’ operation at 2 V makes it suitable for low-power devices with a high potential to be applied in future commercial room-temperature VOC gas sensor devices.

Design of automated power factor monitoring and repair tool for industry in real time based on Internet of Things

The current electricity crisis is caused by the following things; The consumption of electrical energy continues to increase, the supply of electrical energy is limited, there is often a waste of electrical energy due to the use of electrical energy that should not be used (wasteful), as well as the need for electrical energy control that can control the electrical load remotely, and the power factor is lacking. Both resulting in reactive power losses and resulting in an increase in electric current which will have an impact on higher conductor energy losses. It has been discussed a lot, but in reality it still happens a lot, it is necessary to save electrical energy in addition to saving costs but also preventing a power supply crisis by making monitoring tools and power factor improvements that can be controlled remotely based on IoT. This study aims to design and design an automatic power factor monitoring and improvement tool for industry in real time based on the internet of things starting from architecture, display monitors and hardware systems as well as conducting feasibility testing. The method used in this study is the ADDIE method (Analysis, Design, Development, Implementation, and Evaluation) through a literature review and analysis approach. The results of this study are expected to provide appropriate design recommendations and have system and material advantages and to be implemented. The impact of this research is that future research will be much better because in this study a feasibility test of the system has been carried out by conducting simulation trials.

Effect of Pulse Current Density on Microstructure of Ti-6Al-4V Alloy by Laser Powder Bed Fusion

This work thoroughly investigated the microstructure of laser powder bed fusion (LPBF) Ti64 alloy induced by electropulsing (ECP) with different current densities. The results show that as the electric current density increases, the small-sized (&lt;10 μm) α′ martensites increase and the large-sized (&gt;10 μm) α′ martensites decrease, resulting in a typical grading microstructure treated by the ECP treatment. The thermodynamic barrier was found to decrease as the electric current passed, recrystallization occurred, and the percentage of small-sized α′ martensites increased. At the same time, the unique electrothermal coupling effect of ECP treatment acted on the needle-like α′ martensites, causing an energy concentration on the tip to break the adjacent α′ martensite and the percentage of large-sized α′ martensites to decrease. When the current density of ECP treatment was 48.37 A/mm2, the grading phenomenon of acicular α′ martensites was the most obvious and its size distribution changed significantly, which simultaneously improved the strength and elongation of LPBF-Ti64 alloy. Thus, the typical grading phenomenon of the α′ martensites plays a decisive role in improving the mechanical properties of the LPBF-Ti64 samples induced by the ECP treatment. The present results provide new information on the ECP processing additive manufacturing metallic materials.

Incomplete electromagnetic response of hot QCD matter

The electromagnetic response of hot QCD matter to decaying external magnetic fields is investigated. We examine the validity of Ohm's law and find that the induced electric current increases from zero and relaxes towards the value from Ohm's law. The relaxation time is larger than the lifetime of the external magnetic field for the QCD matter in relativistic heavy-ion collisions. The lower than expected electric current significantly suppresses the induced magnetic field and makes the electromagnetic response incomplete. We demonstrate the incomplete electromagnetic response of hot QCD matter by calculations employing the parton transport model combined with the solution of Maxwell's equations. Our results show a strong suppression by two orders of magnitude in the magnetic field, relatively to calculations assuming the validity of Ohm's law. This may undermine experimental efforts to measure magnetic-field-related effects in heavy-ion collisions.

Athermally enhanced recrystallization kinetics of ultra-low carbon steel via electric current treatment

The direct application of electric current as well as heat treatment can be used to recrystallize metallic materials. Electric current enhances the recrystallization kinetics, making the process time- and energy-saving. The enhanced recrystallization kinetics observed during electric current treatment cannot be explained by Joule heating alone, and its quantitative analysis is yet to be conducted. This study systematically investigates the athermal effect of electric current on the recrystallization kinetics of ultra-low carbon steel. Specimens were subjected to electric current at various current densities to reach the target temperatures, and the resulting recrystallization kinetics were analyzed. A comparison with the specimens heat-treated at comparable target temperatures clearly shows that electric current treatment enhances the degree of recrystallization, and the recrystallization kinetics have a unique tendency to decrease and then increase as the electric current density increases. From the recrystallization fraction difference between the electric current-treated and heat-treated specimens, we deduce the athermal effect of the electric current on recrystallization and describe the athermally enhanced recrystallization kinetics using the Johnson-Mehl-Avrami-Kolmogorov equation considering the effective activation energy and temperature. The calculated recrystallization fraction implies that the athermal effect of the electric current becomes more pronounced with increasing electric current density. This study suggests that the athermal effect of electric current in the material fabrication process can be evaluated and predicted.

Unusual electrode-dependent deformation of 3Y-TZP induced by weak electric current in oxygen-lean atmosphere

The plastic deformation behavior of 3Y-TZP with weak electric current in oxygen-lean atmosphere was investigated. The results demonstrated that a weak electric current (I=1 A) can significantly promote the plastic deformation of 3Y-TZP at furnace temperature of 1200 °C and a strain rate of 6.67 × 10−4 s−1. As the electric current increases (1–5 A), the flow stress of plastic deformation has a significant decrease. Especially, a remarkable electrode-dependent deformation near the cathode side was observed for the first time. This unusual phenomenon is mainly attributed to the enhancement of the cation diffusion caused by the electric current-induced electrochemical reduction reaction. In addition, this phenomenon may provide a new method to control the local plastic deformation by controlling the electrode direction and the deformation atmosphere.

Study on supercapacitance performance of TiO2 nanotube arrays modified by non-metal doping and Polyaniline electrodeposition methods

Highly ordered TiO2 nanotube arrays were synthesized by a two-step anodizing method. Although TiO2 nanotubes have excellent electrical and capacitive properties because they provide a unidirectional path for electron transfer. But these properties can be improved by effective methods such as non-metallic doping or by a conductive polymer. For this purpose, nitrogen and hydrogen doping methods and electrical deposition of polyaniline were used simultaneously to prepare the polyaniline-TiO2, polyaniline/N-TiO2, and polyaniline/H-TiO2 nanotube arrays samples. To evaluate the electrochemical and capacitive properties in more detail, cyclic voltammetry, electrochemical impedance spectroscopy, Matt-Schottky, and galvanostatic charge-discharge tests were performed. The results showed that the composite of TiO2 doped with hydrogen and deposited with polyaniline nanowires had the highest capacitance (5666 µF.Cm-2) at the current density of 100 µA/cm2, approximately 4.5 times more than polyaniline/TiO2 sample. It also has the lowest charge transfer resistance (0.008 Ωcm2) and the highest charge carrier density (1.63×1024cm-3). Increasing the density of charge carriers and decreasing the electrical resistance can be attributed to the fact that the hydrogen doping, the presence of oxygen vacancies, and conductive polymer increase the rate of separation of the charge carriers and decrease their recombination rate. Therefore, the electron transfer rate and the electric current increase.

KAJIAN SUSEPTIBILITAS MAGNETIK PASIR BESI PANTAI ARTA SEBAGAI FUNGSI JARAK DARI TEPI LAUT

Magnetic Susceptibility measurements and the identification of elements of iron sand from Arta beach of Pariaman West Sumatera have been done. The samples were dried first under the sun before the separation between magnetic particles of iron sand and non-magnetic particles using Iron Sand Separator. Identification elements of iron sand was done using X-Ray Fluorescence. The total value of magnetic induction was measured using a magnetic Pasco probe PS-2162 using a solenoid 2000 coils turns, dimensions of 3 cm in diameter and 10 cm in length. The solenoid was given an electric current with variations ranging from 2 A – 8 A. The distance between magnetic probe and one end of solenoid was kept constant that was 1 mm. The next experiment was to measure the function of distance ranging from 1 – 5 mm with constant applied current of 8 A. When electric current increase then the total magnetic induction also increase. Total magnetic induction value decreases as the distance increases. Magnetic susceptibility was calculated based on total magnetic induction and magnetic induction of core currents with constant current of 8 A and distance of 1 mm. The value of magnetic susceptibility obtained in the range (2164,71-3159,99)x10-5 which consist of ilmenite mineral (FeTiO3; Antiferromagnetic).Keywords : iron sand, magnetic suseptibility, iron sand separator, solenoid, magnetic induction, and x-ray fluorescence.

Melt dripping behavior in the process of flame spread over energized electrical wire at different pressures

SummaryMelt dripping of polymer insulation in electrical wires is impacted by some factors, such as ambient pressure and electric current. The motivation of this paper is to investigate and discuss the effect of these factors on melt dripping characteristics in the process of flame spread over electrical wire. The results show that the number of dripping times and dripping frequency generally increase with ambient pressure reduced. No dripping phenomenon occurs when the ambient pressure is below 40 kPa at any electric current or is above 70 kPa without electric current applied. There is a good parabolic correlation between the ambient pressure and dripping frequency. The equilibrium temperature of conductor resulted by electric current increases with electric current. A critical electric current found to divide the temperature rate into two regimes is about 8 A. The dripping period and dripping frequency depend on the electric current. The dripping frequency fits well with electric current using a power‐law function. The numerical data are consistent with the experimental data. Besides, the decrease in dripping frequency is greater with ambient pressure at reduced electric current, whereas at larger electric current, the electric current, rather than the ambient pressure, dominates the increased dripping frequency.

A novel cholinesterase assay for the evaluation of neurotoxin poisoning based on the electron-transfer promotion effect of thiocholine on an Au electrode

A simple and cost-effective cholinesterase assay is presented. Thiocholine (TCh), which is generated from substrates by the action of cholinesterase, promotes the electron transfer between [Fe(CN)6]3–/4– and Au electrodes. The electric current increases with the TCh concentration; therefore, the current decreases when cholinesterase is inhibited by neurotoxic chemicals, such as organophosphorus and carbamate compounds. First, we monitored the responses of acetylcholinesterase to cholinesterase inhibitors. The substrate acetylthiocholine was digested with acetylcholinesterase in Tris−HCl buffer, then the reaction mixture was combined with acetonitrile. A polished Au electrode was immersed in the mixed solution for 30 s to immobilize the enzymatic hydrolysis product, TCh, on the electrode surface. The electrode was then subjected to differential pulse voltammetry in 0.5 mM [Fe(CN)6]3– in the presence of KCl as a supporting electrolyte, with a concentration as low as 1 mM. The optimum conditions for the enzymatic treatment were for 10 min at 30 °C with 1.25 mU/mL acetylcholinesterase and 100 μM acetylthiocholine as final concentrations. The inhibition of acetylcholinesterase activities from DDVP (organophosphorus) and methomyl (carbamates) could be monitored. This system was applied to human serum samples containing butyrylcholinesterase. The inhibition of butyrylcholinesterase by DDVP and methomyl were successfully monitored even in human serum. Finally, real human blood donated by 10 volunteers were subjected to a cholinesterase assay using this system. The results from the present method showed good correlation with those obtained from the conventional method using 5,5′-dithiobis-(2-nitrobenzoicacid). The present method was considered valid as a novel ChE assay for human blood.

Microstructural feature and tribological behaviors of pyrolytic carbon-coated copper foam/carbon composite

A novel sliding contact material of pyrolytic carbon (PyC)-coated copper foam/carbon composite was fabricated by a chemical vapor deposition (CVD) technology, followed by several densifying processes of furan resin impregnation and carbonization. Microstructure, electrical and thermal conductivities and current-carrying tribological performance were investigated. The results show PyC crystallites are evenly arranged on the copper foam surface after the CVD process. Because interface wettability between the copper foam and resin carbon matrix is improved by the PyC layer, the composite has a dense structure and a good interface bonding. The composite has obviously more advantages than the carbon-based pantograph strips in the density, electrical and thermal conductivities, due to the copper foam with three-dimensional structure. Friction and wear behaviors were investigated using a current-carrying friction tester. As the electrical current increases, wear rate and wear surface temperature continually increase, and friction coefficient changes from wildly fluctuating to stable. The high electrical current causes high temperature of wear surface and severe wear of oxidization and arc erosion. Copper oxide particles can improve wear surface roughness and change the sliding friction to the rolling friction between the friction couples. In addition, two physical models are schematically illustrated to understand wear mechanism during the current-carrying friction tests.

Oxygen-Resistant Electrochemiluminescence System with Polyhedral Oligomeric Silsesquioxane.

We report the oxygen-resistant electrochemiluminescence (ECL) system from the polyhedral oligomeric silsesquioxane (POSS)-modified tris(2,2′-bipyridyl)ruthenium(II) complex (Ru-POSS). In electrochemical measurements, including cyclic voltammetry (CV), it is shown that electric current and ECL intensity increase in the mixture system containing Ru-POSS and tripropylamine (TPrA) on the indium tin oxide (ITO) working electrode. The lower onset potential (Eonset) in CV is observed with Ru-POSS compared to tris(2,2′-bipyridyl)ruthenium(II) complex (Ru(bpy)32+). From the series of mechanistic studies, it was shown that adsorption of Ru-POSS onto the ITO electrode enhances TPrA oxidation and subsequently the efficiency of ECL with lower voltage. Moreover, oxygen quenching of ECL was suppressed, and it is proposed that the enhancement to the production of the TPrA radical could contribute to improving oxygen resistance. Finally, the ECL-based detection for water pollutant is demonstrated without the degassing treatment. The commodity system with Ru(bpy)32+ is not applicable in the absence of degassing with the sample solutions due to critical signal suppression, meanwhile the present system based on Ru-POSS was feasible for estimating the amount of the target even under aerobic conditions by fitting the ECL intensity to the standard curve. One of critical disadvantages of ECL can be solved by the hybrid formation with POSS.

Thermally induced vibration and strength failure analysis of thermoelectric generators

Thermal vibration and the strength failure of a thermoelectric generator (TEG) subjected to the time-dependent heat flux is discussed in this paper. The heat flux is considered as varying along the circumference of the circular cross section of the TEG, which consists a series of n-type and p-type thermoelectric elements. Vibrations that are parallel and perpendicular to the gravity direction are analyzed, respectively. Analytical and simplified solutions of the vibration deflections of the TEG are given. The maximum principal stress in the TEG is derived analytically. Based on the criterion of maximum principal stress, the envelop curve of heat flux and electric current density corresponding to failure strength of the TEG is obtained. It is found that the vibration deflection is proportional to the heat flux and the value of square electric current. The thermal vibration reduces the output power of the TEG but it only has effect on the output power in a very short time. A bigger damping ration results in a smaller maximum principal stress. The maximum principal stress does not vary with the damping ratio if the length of TEG is small. The critical heat flux and electric current density increase and finally trend to constants with damping ratio.

INVESTIGATION OF THE STRUCTURE AND THERMOPHYSICAL PROPERTIES OF CROSSLINKED POSS-CONTAINING POLYURETHANES

One of the promising scientific directions is the creation of hybrid organo-inorganic materials. This expands greatly the range of properties that are required for modern technological requirements. The biggest obstacle in creating such materials is the complexity of ensuring the uniform distribution of the phase of different nature because of their thermodynamically incompatible. Therefore, in recent days there is considerable interest in hybrid organo-inorganic materials, in which one of the phases has nanoscale. This allows to combine the properties of the organic and inorganic phase at the molecular level. This method leads to increasing of rigidity and strength of materials, their protective properties are improved, the level of conductivity of electric current increases or their cost is simply reduced.Research in the direction of the creation of nanostructured hybrid organo-inorganic systems and nanocomposites received a new impetus in the appearance of polydal oligomeric syssquioxanes (POSS). Due to the possibility of injecting polydrug nucleus of silscvioxanes to side groups of various nature, it is possible to regulate the degree of affinity of sialsecvioxanes with a polymeric matrix and to program the structure and properties of hybrid materials at the nanoscale. Also, due to such features of POSS it is possible to receive hybrid materials on their basis with different morphologies: linear, branched, cross-linked and star-shaped systems.Among the silicon-containing substances, POSS occupy an intermediate position between siloxanes and silicates. On the other hand they can be attributed to spherical siloxanes because they consist from polyhedral structures that are morphologically equivalent to the sphere. Due to the presence of functional groups it is possible to rid the significant lack of siloxanes (not form fibers and films) because of their low intermolecular interaction. Syscvioxanes can be processed at lower temperatures, both in pure form and in mixtures, and also they do not contain traces of metals. Systems based on polymers and POSS have synergistic properties (they are capable of self-rganization). The ability to self-organize of the systems on the basis of the POSS is very important. It allows to receive organo-inorganic materials with a more perfect structural hierarchy . In this work it were synthesized cross-linked hybrid organo-inorganic systems, which can be further used to obtain proton-conducting membranes of hydrogen engines.The method of X-rays scattering in large corners and the method of differential scanning calorimetry (DSC) were used to study the structure of the obtained materials. It was established that the general amorphism of the fine structure of the investigated PU is due to the ability of the mixture of oligosilvesquioxanes to decrease the density of the polymer matrix, and the insignificant ability of the mixture of POCs to create crystals and crystallites.

The Effect of Cable Section on the Variation of Power Automotive Connector Temperature

Electric car requires more electric power. However, the automotive connector that is used to connect two electrical systems should resist the high electric power or electric current. The increase in electric current can lead to an increase in contact temperature by the Joule effect and can cause more damage to an improperly designed connector. The objective of this work is to study experimentally and numerically the influence of cable section on the connector capacity to pass high current. Thus, to study this phenomenon, a finite-element model of power automotive connector with cables and crimping zones was developed to calculate contact resistance and contact temperature. The comparison between the experimental and numerical results shows a good agreement for all tested electric currents. The obtained results lead us to use only the developed numerical model to estimate the value of contact resistance and contact temperature for different cable sections. Moreover, the developed model is beneficial financially. Finally, results have illustrated that the effect of the cable section on the decrease in contact temperature and contact resistance is not negligible.

Gradual Pre-eruptive Phase of Solar Coronal Eruptions

Physical background of the evolution of a coronal magnetic flux rope embedded in the magnetic arcade during the gradual-rise pre-eruptive stage is studied. It is assumed that this stage represents an externyly-driven evolution of the preeruptive structure through a series of quasi-equilibrium states, until a point when system losses equilibrium and erupts. In particular, three driving processes are considered: twisting motions of the flux-rope footpoints, emergence of new magnetic flux beneath the flux rope, and the mass leakage down the flux-rope legs. For that purpose, an analytical flux-rope model is employed, to inspect how fast the equilibrium height of the structure rises due to the increase of the poloidal-toaxial field ratio, the increase of axial electric current, and the decrease of mass. It is shown that the flux-rope twisting itself is not sufficient to reproduce the rising speeds observed during the pre-eruptive stage. Yet, it is essential for the loss-ofequilibrium process. On the other hand, the considered emerging flux and the mass loss processes reproduce well the rate at which the pre-eruptive structure rises before the main acceleration stage of the eruption sets in.